Sahel Drought - worst of the 20th Century

One of the worst environmental disasters of the last century was the Sahel Drought. A million people were directly killed by the drought that lasted a dozen years, from the late 1960s through to the early 1980s, and 50 million more were adversely affected in several countries in a wide swathe of sub-Saharan Africa.

The sudden shift in climate that brought this disaster about has come to be known as 'Abrupt Climate Change', a phenomenon that has been attracting the attention of scientists and world leaders along with the development of global warming science - as the latter exacerbates the former. A scientifically challenged version of this phenomenon was recently 'Hollywood-ised' in the movie The Day After Tomorrow, where a sudden shift in ocean current temperatures brought an instant ice-age upon the northern regions of the planet.

Hollywood aside, where many think of Global Warming as a gradual, almost imperceptible adjustment in temperature, the phenomenon is expected to increase the frequency and severity of regionalised abrupt climate change events.

Scientists looking at this issue have just put out a report, apparently the first of its kind, that indicates abrupt climate change events are a lot more common than initially believed.

Ocean currents play a big role regional weather phenomena

Dramatic as this single event was [the Sahel Drought], University of Wisconsin-Madison researchers have now uncovered 29 other regions worldwide that endured similarly precipitous climatic changes during the 20th century - far more than scientists previously thought. Their study publishes March 30 in the online edition of Geophysical Research Letters.

The work represents the first systematic survey of abrupt climate changes that have occurred in recent history, says postdoctoral researcher Gemma Narisma, who led the study with professor Jonathan Foley, director of the UW-Madison Center for Sustainability and the Global Environment in the Nelson Institute for Environmental Studies. The National Academies' National Research Council has called for more research on abrupt climate change, warning that it's more likely to happen as global temperatures rise and humans continue to alter the environment.

"This study is important, because previous work largely focused on ancient climates or theoretical changes in future climates," says Foley. "But our work here is showing that abrupt climatic changes are real, are with us today, and that they have major impacts on human societies."

By identifying diverse regions around the globe where rapid climatic shifts have taken place, the study opens up new opportunities for understanding why these changes happen and what makes areas susceptible to them, says Narisma. A range of factors is likely involved, including human activities, such as deforestation and land degradation, and natural phenomena, like sea surface temperatures.

The work might also lead to interventions that would make systems less vulnerable to sudden climate change, Narisma adds. - Science Daily

The recent Working Group II release of the IPCC report makes clear that global warming has advanced sufficiently so that mitigation alone will not suffice to protect us from present and future impacts. Adaptation also needs to be part of our strategy. Building resilience into our social and environmental systems should be a key aspect of both mitigation and adaptation strategies.

Both of the major droughts mentioned in the article above (the Sahel Drought, and the 1930's Dustbowl disaster in the U.S. mid-west) were either caused or exacerbated by poor land management techniques.

1930's Dustbowl saw much of mid-west topsoil blown into Atlantic Ocean

Organic agriculture can play a role in mitigating the impacts of land degradation and global change. Organic agriculture increases the resilience and stability of the production system, thus decreasing the vulnerability of small farmers to natural disasters and other disturbances.... For example, after Hurricane Mitch hit the lands of Central America, farmers who used traditional cropping methods suffered less damage than their neighbors who used conventional techniques. The sustainable plots had on average more topsoil, greater soil moisture, and less erosion, and experienced less economic losses....

In addition to mitigating the effects of global change, organic agriculture also directly ensures environmental sustainability. The environmental benefits of organic agriculture have been widely documented and include the provision of ecosystem services, and reduced energy use.... - Organic Agriculture & the Millennium Development Goals, IFOAM (325kb draft PDF)

 

Further Reading:

• Abrupt Climate Change FAQ